Machine tool drive unit



Jan. 2, 1945.

w. c. HE ATH MACHINE TOOL DRIVE UNIT 2 Sheets-Sheet 1 Filed Feb. 9, 1942 AT TORNE Y Jan. 2, 1945. w. c. HEATH MACHINE- TOOL DRIVE UNIT 2 Sheets-Sheet 2 Filed Feb. 9 1942 William (LHeafh' INVENTOR.

BY p x Z ATTORNEY.

Patented Jan. 2, 1945 William 0. Health, Shorewood,-Wis., assignor to i A. 0. Smith Corporation, Milwaukee, Wis., a

. corporation ofNew York I Application February 9, 1942, Serial No. 430,098

.2 Claims. (01. M ume) This invention relates to a machine tool drive unit or more particularly to a power drive that may be employed with machine tools of variable orsingle speeds. I I t I I f One object of the presentinvention is to provide a machine tool drive unit that iseconomical to construct, light in weight and compact upon assembly.

Another object is I to provide aflmachine tool drive unit with a flexibility that: adaptsit for I driving variousand sundry machine tools.

I A further object isto provide a machine tool drive unit that is readily assembled or disassembled for cleaning or repair purposes. I I Another objectis to provide a belt drive in which the tightnessof the belt can be more readily maintained. I

Further objects will appear from the following description and accompanying drawings illustrating an embodiment of the invention. I

In the drawings: I I t Figure 1 is a;horizontal longitudinal section of amachine tool drive unit constructed in accordance with the invention: I

Fig. 2 is a section takenon line 22 of Fig. 1; Fig. 3-is asectional view through the shifting mechanism taken on line 3-3 of Fig. '1; I 1

Fig. 4 is a sectional view of the machinetaken at the gear transmission endthereof on the line 4-4 ofFiggs; and I c i Fig. 5 is a section taken on l'ine 5-5 of Fig. 3. j

I The machine tool drive unit. illustrated, comprises a tubular housing I having a gear case 2 constituting a head atone end and a plate 3 Q constituting a head at the opposite end. Within the housing I and off to one side of the rotational axis thereof is a longitudinally disposed drive shaft 4. I

One end portion of the drive shaft l rests in the bearings 5 carried by the gear case 2 and the other end of the drive shaft is mounted in the cylindrical bearing 6 disposed within the housing I adjacent the end plate '3. The latter end of the drive shaft 4 projects through an opening provided in the end plate 3 to carry the pulley I engaging the belt 8.

.The housing I is mounted for rotation in the I friction bearings 9 within the casing I0. For assembly purposes the housings has a circumfer ential shoulder II which engages the end of the casing I8 at one bearing 9. A retaining collar I2 slips over the plate 3 of thehousing and is secured thereto by suitable set screws I3, so as to engage the other end of the casing III at the,

other bearing 9 and prevent relative longitudinal movement between the housing andcasing.

The tubular members I4; provide adjustable supports for theunitand are .of the generalnature of those disclosed in the co-pending application filed by the same inventor ,on February 9, 1942, Serial No. 430,097 for Machine-tool drive support, and issued to Patent No. 2,353,465, on July 11, 19.44. I i I The casing I0 carries a worm. gear shaft I5 at the pulley end of the machine tool drive unit. I I Oneend of the gear shaft I 5 extends outside the.

casing I0 and has a suitable. operating device,

such as the hand wheel I6 secured thereto. The

other end of the gear shaft I5 is disposed within thelcasing I0" and is provided with the worm gear I1 which meshesinto the complemental gear segment I8 secured to the housing I.-

The manipulation of the hand wheel I6 turn the worm gear I! which in turn moves the gear segment I8 secured to the housing I, thereby rotating thehousing I on its rotational axis in the friction. bearings 9. .The drive shaft l, being to one side of the rotational axis of the housing,

movesbodily in the path of an arc around this axis, to thereby tighten or loosen the pulley belt 8 carried by the pulley I and engaging a pulley on the machine to be, driven by the machine tool driveunitnot shown. In the embodiment illustrated in Fig. 2', if the wheel I6, is turned clock- I Wise, the shaftA moves counterclockwisein an are around the rotational axis of the housing to tighten the pulley belt. If the wheel I Ii is turned counterclockwise, the shaft turns clockwise to loosen the belt.

The drive unit of the present machine prefer ably consists of an elongated electric motor I9 and a gear transmission by which power is transmitted from the motor to the drive shaft 4 actuatingthe pulley I. I

One end of the motor shaft 2|] rests in the bearing 2| disposed in theend plate 3. t The end plate 3 constituting one head of thehousing is specially adapted to receive the end of themotor shaft 5 20 and the nut 22 threaded onto the end of the shaft prevents longitudinal movement of the i shaft in the bearing .21. I II Thefan 23 disposed on the shaftilladiacent the bearing 2|, in combination with the air, holes 24 inthe end plate 3 and in the opposite end of the housing I cool the motor I9 during operation. I. I v

The other endofthe motor shaft 28 is mounted in the ball bearing 25 disposed at the gear end of the housing I and the nut 26 threaded onto A series of gears 32, 33 and 34, of varying size.

may be splined to the countershaft 36, as illustrated. These gears mesh respectively with the complemental gears 35, 36 and 31, disposed on In the operation of the machine shown and described, the belt 8 passing around the pulley I is slipped over the pulley of the machine to be driven and the supports l4 are adjusted to move the drive unit in such a manner that the pulley belt 8 will be reasonably loose.

The wheel l6 disposed on the outside of the drive unit is next turned clockwise. This rotation of the wheel turns the worm gear shaft l5 carrying the worm gear I! meshed into the gear segment I 8 secured to the motor housing I, thereby moving the latter and causing the gear segment Is to describe an are around therot'ational the drive shaft 4 in spaced relation to drive the shaft at different speeds.

The gears 32, 33 and 34 are put into driving connection with the gears 35, 36 and .31, respectively, by operation of the hand wheel 38. The hand wheel 38 is connected to the outer end of a shaft 39 projecting through the gear case 2. The body'portion of the shaft 39 carries a spring 40 between the head 2 and the hand wheel 38 to bias the shaft outwardly from the head 2, and the inner end of the shaft 39 is suitably secured to a crank 4|.

The outer end of the crank 4| has a fork 42 for engaging a pin 43 on the shift block 44. The shift block 44 is disposed and longitudinally movable on the shaft 45. The shift block has an arm constituting a fork 46 extending on either side of the countershaft between gears 32 and 33 to move the group of gears 32, 33 and 34 longitudinally onrthe countershaft.

The crank 4| in its body portion carries the pin 41 whose projecting end fits into the aperture 48 cast in the gear case 2. In the embodiment illustrating the invention there are three apertures 48 to match the three gear ratios of the gear train.

The wheel 38 is pushed in to dislodge the pin 41 from one of the apertures 48 which the pin engages. The wheel is then turned to move the crank 4| and fork 46 and thereby move the group of gears 32, 33 and 34 longitudinally on the countershaft 30- until one of these gears engages one of the complemental gears 35, 36 or 37 on the drive shaft 4. mesh, pressure on the wheel 38 is released and the spring moves the shaft 39 with crank 4| outwardly, thus forcing the pin 41 into the respective aperture 48. This holds the gear train in place while the unit is in operation.

The center gear 33 carried by. the countershaft 3B is larger than either the gear 32 or '34. This permits the gears 32 and 34 to be moved past the gear 36 on the drive shaft 4 complemental to the gear 33, to put the gear 32 in driving connection with the gear 35 and the gear 34 in driving connection With the gear 3?. Due to the different gear ratios between the respective pairs of gears 32-35, 33-36 and 34--3'|, the shaft 4 may be rotated :at different speeds depending upon which gear is driving the shaft.

'When the desired gears are in,

axis of the housing. Since the drive shaft 4 carrying the pulley 1 engaging the belt 8 is disposed in the housing I to one side of the rotational axis thereof, the shaft 4 moves bodily coungears 35, 36 or 31 on the shaft 4 to drivethe shaft.

The start switch. in the control box 43 is then pushed to put the electric motor IS in operation. Power is transmitted from the motor to the countershaft and thence to the drive shaft 4 by the system of gears described to drive the shaft at the speed desired and revolve the belt engaged by the pulley connected to one end of the drive shaft. 1

If different speeds in the drive. shaft are desired the handwheel. 38 is operated to put into driving connection either the gears 32-35 or 33-36 or 34- -31, depending upon which set of gears has the desired speed.

The invention has numerous advantages. In the event that it is necessary to clean or repair any part of the unit, the motor and gear transmission parts may .be easily and quickly removed by merely unbolting the heads at the ends of the housing and then removing the parts which secure'the motor, gear transmission anddrive shaft within the unit. I i

The gear transmission is located at. the opposite end of the unit from that of the pulley; permitting removal and assembly of the gears without disturbing the mounting of the motor and the drive shaft carrying the pulley. The gears Any other suitable shifting mechanism pro- 'viding speed changes may be employed as the change speed mechanism here described is not essential to carry out the invention. If only ga countershaft to the drive shaft may be employed.

The unit has a control box 49 secured-to the 3 outside of the casing Ill with switches for starting, stopping or reversing the electric motor i9.

of the unit are also mounted in aseparate com-.-

partment for running in oil the motor.

The invention may be employed with chain Without injury to drives as well as with belt drives. The invention may have various embodiments for rotation in ,a sleeve encircling the same, a

power drive unit including an electric motor within the housing and having a main drive shaft extending parallel to and to one side .of the rotational axis of the housing, a member to bedriven by said shaft, and a handoperated Worm gear disposed in an opening in said sleeve and mesh- 2,366,527 i 3 speed transmission at one end of said motor and disposed in a detachable casing secured to the end of the motor housing to drive said main shaft from said motor, a member. to be driven by said a main shaft at the end of said motor opposite said transmission, a bearing encircling said m0- tor housing between the ends thereof to support the same for rotation on an axis offset from said main drive shaft, and a manual adjusting device connecting said bearing andmotor housing for rotating the latter to a position for connecting said drive shaft to said member to effect operation of the latter, i

a WILLIAM C. HEATH. 

